1. Field of the Disclosure
The disclosure relates in general to trenching equipment and methods, and more particularly, to a system and method of forming an underground slurry wall which includes the mixing of outside material into an existing soil base through a trenching operation.
2. Background Art
The formation of underground slurry walls is well known in the art. An underground slurry wall is a non-structural wall that is a barrier to the movement of groundwater thereacross. Typically, the existing soil is mixed with an outside material (usually a clay-like material, such as bentonite) and then reintroduced into the trench. The addition of the outside material (hereinafter referred to as bentonite, although other materials are likewise contemplated) provides a barrier to the movement of horizontal groundwater. Additionally, for purposes of this material, clay-like material shall be defined as including bentonite, as well as other materials which may be natural or synthetic which are introduced into the soil during trenching so as to provide barrier properties to the soil. The disclosure is not limited to bentonite or to materials which include clay per se.
There are a number of manners in which to introduce the bentonite into the ground soil. For example, a deep trench may be dug, bentonite can be deposited into the deep trench, or mixed with the excavated soil, wherein the mixture is returned to the trench. It is understood that such a method may work for relatively shallow trenches, as it is difficult to dig deep trenches through such a method, and even for relatively shallow trenches, additional equipment, such as bracing and the like is required.
Other methods have a double trench approach. First a shallow trench is dug and bentonite is deposited into the shallow trench. Next, that trench may be backfilled so as to bury the bentonite. Once buried, a second trench is dug at the same location only deeper with trenching equipment that effectively mixes the bentonite through the entire depth with the existing soil. While such a trenching system is capable of use in deeper trenching environments, it is nevertheless less than optimal, as two separate trenches are required; first, a shallow trench to bury the bentonite, then a second deep trench on top of that trench to mix the bentonite to form the underground slurry wall. In many instances, such an approach results in extended time schedules, and often results in a very costly operation.
It is an object of the present invention to provide a relatively deep underground slurry wall, while mixing an outside material (such as bentonite) while forming the underground slurry wall in a single operation, while making a single pass across the landscape.
This objects as well as other objects of the present invention will become apparent in light of the present specification, claims, and drawings.